[DATE, ex. Monday, March 31, 2008]

[NAME, COMPANY AND ADDRESS, ex.
Link Building
XYZ Inc.
1234 First Street
Suite 567
Anycity, Anystate  85245]

Dear [NAME, ex. Link Building],

I would like to thank you for your referral to [FIRM, ex. ABC Co].  [MENTION WHAT OCCURRED AND WHAT YOU WILL DO AS A RESULT OF THE REFERRAL, ex. On your suggestion, I have spoken with Mr. Holmes and forwarded my resume to the human resources department.  I hope to be hearing from them soon.]

I will keep you up to date as to what happens.  Thanks again.

Sincerely,

[YOUR NAME, ex. Jill Jones]